There are two main situations about a day of the week:

One case is different years in the same month: one year+1, a leap month (leap year February)+1;

Another situation is that the year is different and the month is different: consider the year first, then the month. The year is considered as the first case, and the month is considered as: +2 after the abortion (abortion means 30 days), recursively using the same principle, without adding after 28 days,+1 after 29 days, 3 1 days +3.

Second, the case analysis

Example: 1, July 2003 1 is Tuesday, so what day is July 2005 1?

A.wednesday, b, thursday, c, friday, d and saturday

Answer c

The analysis of this topic belongs to the first case, that is, from 2003 to 2005, after two years, add 2, of which after 2004, that is, in February of leap year, add 1, so add 3 to one * * * and add 3 to Tuesday, that is, Friday.

Example 2: It is known that New Year's Day in 2008 is Tuesday. When is New Year's Day in 2009? ()

A Tuesday b Wednesday c Thursday d Friday

Answer c

The analysis of this problem belongs to the first case, that is, the same month and different years. From 2008 to 2009, 1 was added one year later. After 2008, that is, in February of leap year, 1 was added, so 2 was added with a * * * Tuesday, that is, Thursday.

Example 3: July 2003 1 is Tuesday, so July 2000 1 is ().

A.wednesday, b, thursday, c, friday, d and saturday

Answer d

In fact, the analysis of this problem belongs to the first case, that is, the same month and different years, but the time is reversed. From 2003 to 2000, the difference was three years, minus 3. Since it is pushed back from July 2003 to July 2000, there is no leap year, so Tuesday is MINUS 3, which is Saturday.

Example 4: June 2003 1 is Wednesday, so what is August 2005 1?

A. Monday B. Tuesday C. Wednesday D. Thursday

Answer d

The analysis of this topic belongs to the second situation, that is, the year is different and the month is different, so the year is considered first, from 2003 to 2005, and 2 is added after two years, in which 1 is added after 2004, that is, in February of leap year, and 1 * * * is added with 3; Considering the month again, add 2 after June (30 days), add 3 after July (3 1 day), and add 5 after 1 month 1 day. So when the year and the month are combined, they always add 8. Wednesday plus 8 equals Monday, and a period minus 7 days equals Thursday.